The present disclosure relates generally to information handling systems, and more particularly to a chassis design relating to network switching products. But it would be recognized that the invention has a much broader range of applicability.
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option is an information handling system (IHS). An IHS generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes. Because technology and information handling needs and requirements may vary between different applications, IHSs may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in IHSs allow for IHSs to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, IHSs may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
With the advent of centralized locations for storing data associated with network services (retail services, financial services, communication/social networking services, database services to name only a few), network devices such as switches and routers are designed to very quickly process and route large volumes of network traffic. Such centralized locations are typically referred to as data centers.
Network switching products form the interconnection backbone in data centers. In order to support large numbers of network switching products, these network switching products are often designed around standard form factors and sizes. Typically these form factors and sizes are designed so that the network switching products can be rack mounted using interchangeable slots. A common feature in the rack-mounted arrangement is a chassis. A typical chassis includes a rigid frame with one or more power supplies and one or more interchangeable slots for receiving a corresponding one or more network switching products. Chassis have been typically designed to provide both flexibility and redundancy in network configuration and operation. By using interchangeable slots, the number and variety of network switching products that are installed is flexible. Not only does this provide the ability to swap out defective network switching products and to upgrade previously installed network switching products, it also provides for the ability to add additional network switching products to previously installed chassis, subject to space availability. In addition, with the advent of hot-swappable network switching products, it is possible to replace a network switching product while the other network switching products in the system remain active and functioning.
One common type of chassis includes a backplane. The backplane is typically a fixed interconnection unit that provides connectivity and routing between the various network switching line cards are inserted into the slots of the chassis. For example, the backplane includes a circuit board with various card edge connectors into which each of the network switching products are inserted. The circuit board generally contains an extensive bus and point-to-point wiring pattern that interconnects pins between the card edge connectors that allow each of the network switching products to communicate. In another example, the circuit board includes power supply wiring for supplying power to each of the network switching line cards. The use of a backplane places certain limits on the capabilities of the chassis to support additional and upgraded network switching products. For example, one such limit is the number of slots (i.e., card edge connectors) provided by the backplane, this is typically fixed in number and provides a finite upper limit on the number of network switching capability the chassis supports. The design of card edge connectors and the backplane circuit board can place additional limits on upgradability due to limitations associated with signal integrity, frequency limits, and the like. Further, the use of a monolithic backplane may interfere significantly with cooling airflow between the front and back of the chassis. Not only does the backplane design impose a high infrastructure cost, but the limitations typically limit the effective life span of the backplane-based chassis.
More recently, chassis design has begun to migrate away from the backplane design to a mid-plane design. In a mid-plane design, the interconnect circuit board is moved from the back of the chassis to near the center of the chassis. For example, network switching products in the form of line cards are inserted from the front of the chassis into card edge, or similar, connectors on the front surface of the mid-plane interconnect circuit board. Additional network switching cards in the form of route processor modules (RPMS) or fabric cards are inserted from the rear of the chassis into card edge, or similar, connectors on the rear surface of the mid-plane interconnect circuit board. In some examples, the interconnect model is orthogonal in nature such that the line cards are inserted into the mid-plane interconnect circuit board in a first orientation (e.g., vertical) and the RPMs are inserted into the mid-plane interconnect circuit board in a second orientation that is orthogonal to the first orientation (e.g., horizontal). As in the case of the backplane chassis, the presence of the mid-plane interconnect circuit board in the mid-plane chassis places the same limits on the chassis related to slot capacity, electrical signal characteristics, and interference with cooling airflow between the front and back of the chassis.
Accordingly, it would be desirable to provide an improved chassis design that provides greater flexibility in slot capacity, increased longevity due to ability to adapt to ever increasing electrical signal characteristics, and/or better support for cooling airflow through the chassis.